The generation of functional images from the time-activity curves of individual pixels in the gated blood-pool study has become a routine part of most nuclear medicine computer systems. These images have the advantage of extracting useful functional information from the entire study and presenting it in an easily interpretable format. One can rapidly examine them, especially the phase and amplitude images, to seek out potential abnormalities of contraction and conduction. These are not designed to be "stand alone" images and correlation with the remainder of the study, including the cine display, is required. In addition to their use in assessing abnormalities of either ventricular chamber, they also have been shown to be useful in delineating atrioventricular borders in both the left and right sides of the heart. This facilitates definition of regions of interest for the calculation of ejection fractions. These images are produced at no increased expense or inconvenience to the patient and therefore should always be evaluated.